Prophylaxis in children with haemophilia in an evolving treatment landscape

[Treatment of haemophilia in Austria]

This guideline is intended to provide practical guidance for the diagnosis and treatment of haemophilia in Austria. Few randomized controlled interventional trials are available addressing the treatment of haemophilia, therefore recommendations are usually based on low level of evidence and represent expert consensus.This guideline is based on the WFH guideline, published in 2020, and adapted according to the national circumstances and experience.It includes recommendations and suggestions for diagnosis and follow-up visits and pharmacological therapies for treatment and prophylaxis. Further topics comprise special aspects in children and adults with severe haemophilia, outcome measurement, and management of trauma, special bleedings and interventions, including dental procedures, inhibitors, management of haemophilia carriers, and psychosocial aspects.

Bleeding control improves after switching to emicizumab: Real-world experience of 177 children in the PedNet registry

INTRODUCTION

Despite the rapid uptake of emicizumab in the paediatric haemophilia A (HA) population, real-world data on the safety and efficacy is limited.

AIM

To report on bleeding and safety in paediatric patients receiving emicizumab prophylaxis.

METHODS

Data were extracted from the multicentre prospective observational PedNet Registry (NCT02979119). Children with haemophilia A, and ≥50 FVIII exposures or inhibitors present receiving emicizumab maintenance therapy were analysed. Data were summarized as medians with interquartile range (IQR, P25-P75). Mean (95% confidence interval (CI)), annualized (joint) bleeding rate (A(J)BR) during emicizumab and ≤2 years before emicizumab prophylaxis were modelled and compared using negative binomial regression.

RESULTS

Total of 177 patients started emicizumab at median 8.6 years (IQR 4.8-13.1), most had no FVIII inhibitors (64%). Follow up before emicizumab was median: 1.68 years (IQR: 1.24-1.90) and during emicizumab: 1.32 years (IQR: .94-2.11). In patients without inhibitors, mean ABR reduced after starting emicizumab from 2.41 (CI 1.98-2.95) to 1.11 (CI .90-1.36, p < .001), while AJBR reduced from.74 (CI .56-.98) to.31 (CI .21-.46, p < .001). Concordantly, in patients with inhibitors, mean ABR reduced from 5.08 (CI 4.08-6.38) to .75 (CI .56-1.01, p < .001), while AJBR reduced from 1.90 (CI 1.42-2.58) to .34 (CI .21-.56, p < .001). Five emicizumab-related adverse events were reported (3% of the cohort), including one patient with antidrug antibodies.

CONCLUSION

This study showed improved bleeding control compared to previous treatment and a favourable safety profile during emicizumab therapy in paediatric haemophilia A patients.

Cost-effectiveness analysis of low-dose prophylaxis versus on-demand treatment for moderate-to-severe hemophilia A in India

AIM

Hemophilia A (HA) is an inherited bleeding disorder caused by a deficiency of clotting factor VIII in the blood. In resource-limited settings like India, affordability is a significant challenge in managing patients with severe HA. This study aims to assess the cost-effectiveness of intermediate-dose prophylaxis versus on-demand factor therapy in adult and pediatric populations with moderate-to-severe congenital HA without inhibitors in India.

METHOD

We conducted a prospective cost-effectiveness analysis from a societal perspective, categorizing patients into a base state and a joint disease state (patients with Hemophilia suffering extensive bleeds leading to chronic joint disease). Using targeted literature search and primary market research, we developed a Markov model measuring the total cost of Hemophilia treatment and health outcomes, including life-years (LYs), quality-adjusted life-years (QALYs), incremental cost-utility ratio (ICUR), and incremental cost-effectiveness ratio (ICER). The model extended over a lifetime horizon of 70 years with a one-year cycle length. Sensitivity analyses assessed study robustness.

RESULTS

Low-dose prophylactic therapy was cost-effective for adults (>18 years) and pediatric populations (<18 years), yielding better health outcomes (adults: 0.15 LYs and 2.43 QALYs gained; pediatric: 0.40 LYs and 3.12 QALYs gained). Intermediate-dose prophylaxis showed positive net monetary benefits in terms of Quality-Adjusted Life Years (QALYs) for both adult and pediatric populations, with dominant ICER and ICUR values in both cases.

CONCLUSION

Using intermediate-dose prophylactic factor VIII therapy is a cost-effective approach that improves clinical outcomes compared to on-demand therapy in the Indian adult and pediatric HA populations without inhibitors.

Evaluation of treatment and outcome for patients with haemophilia A and haemophilia B on extended half-life (EHL) factor products: A 12-month data analysis

INTRODUCTION

Extended half-life (EHL) factor VIII and IX concentrates as prophylaxis against bleeds have been available to selected persons with haemophilia (PWH) in Australia since March 2018. Preliminary analysis of switching to EHL demonstrated increased treatment adherence, fewer injections and improved bleeding outcomes.

AIMS

To characterise clinical practices regarding the use of EHL in Australia, to further evaluate treatment regimens and bleeding outcomes, and to analyse the influence of EHL product pharmacokinetics on clinical decision-making.

METHODS

A national, retrospective study was conducted using the Australian Bleeding Disorders Registry (ABDR). Patients on EHL products during the entire 2019 calendar year were included for analysis.

RESULTS

A complete and validated dataset of 174 PWH was analysed, 115 Haemophilia A (HA) and 59 Haemophilia B (HB). Adherence to EHL therapy was 85.7% in HA and 87.2% in HB. About 63.5% of HA and 64.4% of HB PWH reported zero spontaneous bleeds over 12months. Ankles were the most frequent spontaneous bleed site. Approximately one-third patients underwent dose adjustments, with most frequent reasons being pharmacokinetics, body weight change and breakthrough bleeds. About 19.5% of PWH had target joint history, with spontaneous bleeds reported in 58% of that cohort on EHL. Multivariate regression showed significant impact of non-adherence, target joint history and short half-life on spontaneous bleeds in the HA cohort; however only short half-life had significant impact in the HB cohort.

CONCLUSION

EHL usage in Australia shows excellent treatment adherence and bleeding outcomes. This study affirms the use and value of widely available population-based pharmacokinetics as a clinical tool.

Factor VIII inhibitors in hemophilia A treated with emicizumab: longitudinal follow-up of outcomes

Background

Using emicizumab in lieu of immune tolerance induction (ITI) for patients with hemophilia A (HA) and factor (F)VIII inhibitors has been well described. However, decisions regarding ITI initiation, regimen, and preservation of tolerance remain to be elucidated.

Objectives

To study the course of FVIII inhibitors in patients with HA and a history of FVIII inhibitors receiving emicizumab prophylaxis.

Methods

Patients with HA, with and without FVIII inhibitors, initiating emicizumab prophylaxis were prospectively followed up in our center. All patients with current or previous inhibitors were included in this analysis. Plasma samples for FVIII inhibitor assays were obtained every 3 to 6 months or following FVIII exposure. Patients documented annual bleeding rate and any FVIII exposure days (EDs).

Results

Of 162 emicizumab-treated participants, 51 met the inclusion criteria. A decrease in annual bleeding rate was observed in all 51 participants followed up for a median of 3.3 years, with 31 breakthrough bleeding episodes reported in 22 of 51 participants. FVIII inhibitor level transiently increased following FVIII exposures in 5 of 15 failed ITI participants. Eight of 21 participants who did not undergo ITI were exposed to FVIII (1-2 EDs)), and 1 of these 8 participants demonstrated increased FVIII inhibitor levels after head trauma (following 1 ED). Among participants who underwent successful ITI, 8 of 15 patients were exposed to FVIII over a total of 13 EDs (1-2 ED(s) each) for traumatic breakthrough bleeds. In all these participants, inhibitor levels remained zero, indicating successful tolerance maintenance.

Conclusion

Our longitudinal follow-up of emicizumab-treated patients with HA and FVIII inhibitors shows that occasional exposure to FVIII may induce a transient anamnestic response. Nonetheless, no FVIII inhibitor recurrence was noted following FVIII exposures in patients who underwent successful ITI.

Emicizumab state-of-the-art update

Introduction

Emicizumab is a bispecific monoclonal antibody developed to address the unmet needs of clotting factor replacement therapy and has become the benchmark for optimal prophylaxis in managing patients with haemophilia A with inhibitors. We describe the emicizumab rollout and pharmacokinetic strategies and their use in paediatric patients.

Methods

The evolving real‐world experience in using emicizumab has confirmed its safety, efficacy and pharmacokinetic profile in paediatric, adolescent and adult patients receiving emicizumab at various prophylactic dosing regimens. The emicizumab current global rollout includes over 100 countries with 29 low to middle‐income countries accessing emicizumab through the World Federation of Haemophilia (WFH) Humanitarian Aid Program. The diversity of emicizumab dosing and pharmacokinetic tools such as the Calibra® and the WAPPS‐Hemo platforms make it possible to achieve prophylaxis goals in line with the WFH Haemophilia treatment guidelines recommendations, with minimal drug wastage. The emerging experience from long term clinical trials and long‐term real‐world follow‐up confirm the safety, efficacy, and pharmacokinetic profile of emicizumab in paediatric haemophilia A patients. A few questions, including inhibitor recurrence, concurrent use of emicizumab with various replacement therapies and inhibitor eradication, are being addressed through multiple ongoing clinical studies.

Conclusion

The current global rollout of emicizumab is remarkable, and versatile dosing regimens and evolving pharmacokinetic tools such as the Calibra® and WAPPS‐Hemo platforms make it a treatment choice available also for pharmacokinetic guided personalised treatment. Data from paediatric studies are consistent with those seen in adolescent and adult Haemophilia A.

Emicizumab for All Pediatric Patients with Severe Hemophilia A

Emicizumab is the first approved nonreplacement therapy for bleeding prophylaxis in hemophilia A (HA) patients. In 2018, it was licensed for HA patients with inhibitors, subsequently followed by an "European Medicines Agency (EMA)" approval for patients with severe HA in the absence of inhibitors in 2019. This is immediately raising the question whether emicizumab is suitable as a first-line treatment for all pediatric patients with severe HA. In this review, we want to discuss what we have, what we know, and what we would like to know. Severe HA is characterized by severe spontaneous and traumatic bleedings, particularly into muscles and joints leading to chronic joint damage. Standard of care is the regular, prophylactic replacement of factor VIII to prevent bleedings. Due to approval of emicizumab-the first nonreplacement therapy for bleeding prophylaxis-in HA patients with inhibitors, and severe HA patients without inhibitors, it is of pivotal interest whether emicizumab could be the first-line treatment in all pediatric patients with severe HA. Clinical trials and real-world observational studies could demonstrate a good efficacy and safety for bleeding prevention during emicizumab treatment in HA patients with and without inhibitors. This clearly indicates that emicizumab could improve HA treatment. However, some crucial and critical questions are remaining with regard to the use of emicizumab. Some of this missing information is already under investigation in the context of clinical trials. Until getting finalized data to shed insights into the points that are currently being discussed, there is a variety of expert and expert group recommendations, which are tackling questions concerning the treatment of HA patients. This review will address major information that is already available, but will also focus on important points that remain to be elucidated in the context of HA treatment.

Transcutaneous ultrasound mediated gene delivery into canine livers achieves therapeutic levels of FVIII expression

Nonviral UMGD can achieve therapeutic levels of FVIII gene expression in a large animal model.

UMGD targeting liver is safe without evidence of any lasting damage.

A safe, effective, and inclusive gene therapy will significantly benefit a large population of patients with hemophilia. We used a minimally invasive transcutaneous ultrasound-mediated gene delivery (UMGD) strategy combined with microbubbles (MBs) to enhance gene transfer into 4 canine livers. A mixture of high-expressing, liver-specific human factor VIII (hFVIII) plasmid and MBs was injected into the hepatic vein via balloon catheter under fluoroscopy guidance with simultaneous transcutaneous UMGD treatment targeting a specific liver lobe. Therapeutic levels of hFVIII expression were achieved in all 4 dogs, and hFVIII levels were maintained at a detectable level in 3 dogs throughout the 60-day experimental period. Plasmid copy numbers correlated with hFVIII antigen levels, and plasmid-derived messenger RNA (mRNA) was detected in treated livers. Liver transaminase levels and histology analysis indicated minimal liver damage and a rapid recovery after treatment. These results indicate that liver-targeted transcutaneous UMGD is promising as a clinically feasible therapy for hemophilia A and other diseases.

Total knee arthroplasty in hemophilia: lessons learned and projections of what's next for hemophilic knee joint health

INTRODUCTION

The purpose of this article has been to review the literature on total knee arthroplasty (TKA) in people with hemophilia (PWH), to mention the lessons we have learned from our own experience and to try to find out what the future of this type of surgery will be.

AREAS COVERED

A Cochrane Library and PubMed (MEDLINE) search of studies related to TKA PWH was analyzed. In PWH, the complication rate after TKA can be up to 31.5%. These include infection (7.1%) and bleeding in the form of hematoma, hemarthrosis or popliteal artery injury (8.9%). In a meta-analysis the revision arthroplasty rate was 6.3%. One-stage or two-stage revision arthroplasty due to infection (septic loosening) is not always successful despite providing correct treatment (both hematological and surgical). In fact, the risk of prosthetic re-infection is about 10%. It is necessary to perform a re-revision arthroplasty, which is a high-risk and technically difficult surgery that can sometimes end in knee arthrodesis or above-the-knee amputation of the limb.

EXPERT OPINION

TKA (both primary and revision) should be performed in centers specialized in orthopedic surgery and rehabilitation (knee) and hematology (hemophilia), and with optimal coordination between the medical team.